Zero-energy nonlinear temperature control of lithium-ion battery based on a shape memory alloy

Improving the poor performance of lithium -ion battery (LIB) in extreme temperatures is essential to promoting electric vehicles (EVs) into wider application. The most severe challenge for the existing battery thermal management systems (BTMSs) is to overcome the contradiction between excellent heat dissipation at high temperatures and effective insulation at low temperatures. Here, we propose a zero -energy nonlinear temperature control strategy based on thermal regulator. The designed thermal regulator based on shape memory alloy (SMA) can switch the heat flux on the battery surface according to its temperature without any power supply or logic control and provide the desirable thermal functions. This thermal regulator increases the battery capacity by 55.44 % in the cold environment of -20 degrees C compared to the baseline BTMS with superior heat dissipation. Simultaneously, it can limit the battery peak temperature to near the FS49 boiling point (49 degrees C) in the hot environment of 45 degrees C to ensure safety. Furthermore, we demonstrate that the thermal regulator enables thermal runaway to be effectively suppressed inside the battery, reducing the emission of combustible or toxic gases by 72.26 %, which is reported for the first time. Finally, we simplify the design of the thermal regulator from the perspective of system integration and demonstrate the feasibility of the thermal regulator at the battery pack level.